Analyzing PCM Data: Notes

Once the fault area is identified, the circuit must be checked to determine if the wiring or component is at fault. When making circuit and component measurements, make sure all accessories and dome and hood lamps are off. Use any of the following methods to diagnose a suspected PCM wire circuit or device. Some methods are particular to a certain type of PCM device.

• Change Condition to Cause Response by Input
• Change Input and Verify Output Response
• Click Testing/Output State Control (Solenoids/Relays)
• Coil Resistance (Solenoids/Relays)
• Harness Opens
• Harness Shorts